* feat(i18n): Enhance Translate mode guidelines
This commit improves the Translate custom mode in .roomodes by adding:
- Clear requirement to use informal speech (e.g., "du" instead of "Sie")
- Guidance on preserving domain-specific terminology in English
- New section on common translation pitfalls to avoid
- Enhanced instructions for handling placeholders in translated strings
- Guidelines for UI element translation (buttons vs. tooltips)
- Directions for handling incomplete source strings
- Rules to preserve original perspective (user→system vs system→user)
- A translator's checklist for quality assurance
These improvements ensure more consistent, accurate, and natural
translations across supported languages while preventing common
localization errors.
* use informal speech in de locales
